The present invention concerns a combination throttle valve and gate valve to be used in a multi-pump chamber such as is typically used in a system to etch semiconductor wafers.
Typically in a process chamber in which silicon wafers are etched, a high flow pump is used to provide air/gas flow through the process chamber and to maintain low pressure inside the process chamber. Throttling of pumping speed is typically done by use of a butterfly valve between the process chamber and the high flow pump. Additionally a gate valve may be stacked up with the butterfly valve between the process chamber and the high flow pump allowing the high flow pump to be isolated from the process chamber, for example, to provide isolation of the process chamber during removal of the pump.
A single pump, however, may not be able to efficiently supply the greater pumping speed or pumping capacity needed for some processes. Further, when a butterfly valve is in series with a gate valve there is a large gate depth dimension, which makes the process chamber system cumbersome.